Pests
Grapholita molesta Busck. - Oriental Fruit Moth.
Systematic position.
Class Insecta, order Lepidoptera, family Tortricidae, subfamily Olethreutinae, tribe Laspeyresiini, genus Grapholita.Synonyms.
Laspeyresia molesta Busck, Cydia molesta Busck.Biological group.
Oligophagous pest of large-fruit rosaceous crops.Morphology and biology.
Forewings dark gray-brown, with 7 pairs of albesent shiny strokes along anterior margin (wingspan 11-15 mm). Wing apex bordered by thin velvety black line; tapetum hardly visible. Hindwings lighter, brown-gray. Egg flattened; fresh egg white, later with orange tint. Caterpillars 9-13 mm in length, hardly differing from caterpillars of the Plum Fruitworm. Pupa brown, with 2 rows of spines on abdominal tergites and with 10-18 spinules at abdominal apex. Fertility is 20 to 360 eggs. Female lays eggs one by one on glabrous surface of leaves at top of young shoots, on bud scales, and later on glabrous surface of fruits. Eggs develop over 6-12 days in spring, 3-6 days in summer, and 5-16 days in autumn. Caterpillars penetrate into young shoots through top bud. On apple and quince they mine leaves at first. In shoots the caterpillar make holes 11 cm long from top down to ligneous tissue. They damage fruits from the moment of ovary formation, where they make cavities, filling them with excrements. The period of caterpillar development lasts 9-12 days on peach, 16-24 days on apple and quince. Diapausing caterpillars of last instar winter in dense silky cocoons. Average duration of development of the pupae of different generations is 3-11 days.Distribution.
The native land of the pest is East Asia (China, Korea, Japan), whence it has widely settled in different countries. Today it lives also in Middle and Southern Europe, Middle East, Northern (the south of Canada, USA, Mexico) and Southern America, Australia, New Zealand, Northern and Southern Africa. In 1964 the pest was found for the first time in the territory of the former USSR (in Sochi district), in 1965 in Azerbaijan, in 1966 in Ukraine, and in 1972 in Armenia. Now the Oriental Fruit Moth has occupied all Ukraine, Georgia, southern Kazakhstan (Almaty, Shymkent Regions), Uzbekistan (Fergana valley), Rostov and Astrakhan Regions, the south of Voronezh Region, Krasnodar and Stavropol Territories, republics of the northern Caucasus. The centers of seasonal colonization are regularly found in Kaliningrad Region, in Byelorussia, in boundary areas of the Far East of Russia, in environs of Moscow and other centers of mass delivery of stone fruits.Ecology.
Within the limits of the species area there are not less than 2 generations; up to 3 in northern Ukraine, 3 to 5 in the south of Ukraine (including Crimea), 4 to 6 in Georgia, Armenia and Azerbaijan. Pupation begins in spring at daily average temperature 9-10°C in Ukraine, 10.5-12°C in Armenia, and coincides with bud blooming of peach and quince. Moths are active at temperatures above 15°C. The moth flight begins in Ukraine and Transcaucasia from mid-April, usually coinciding with the termination of flowering of peach. Duration of embryonic development is 6-12 days in spring, 3-6 days in summer, 3-16 days in autumn. Life span of moths is 7 days in summer and about 25 days in autumn (20 days on the average). The upper threshold temperature for moths is about 36°C. Moths are coupled in evenings. The lower threshold temperature for egg laying is 13.1-16.5°C. At relative air humidity less than 70% the egg laying stops, and caterpillars may get summer diapause. Degree days for full cycle of development are 338-383° (above 10°C). Temperature optimum with high humidity is 24-29°. From the end of August some of the caterpillars finish their feeding diapause. Factors limiting the species distribution are low frost resistance of wintering caterpillars and hygrophility of active summer stages of the pest.Economic significance.
Caterpillars damage fruits and young shoots of various rosaceous cultures, such as peach (preferred), quince, pear, plums, and also apricot, apple, biwa, cotoneaster. On cherry, sweet cherry, cherry-laurel, and on almonds they live mainly in shoots, on hawthorn they live in fruits only. In total the species damages over 80 cultures. Yield losses reach 30-40% in many areas, sometimes 50-60%. The damage rate depends on terms of ripening. The greatest harm is recorded in areas of joint growth of peach and apple, pear, or quince. Control measures are as follows. Agronomical: deshooting and burning of damaged shoots, use of trapping bands and cleaning of trunks from old bark, gathering and destruction of fruit drop. Biological: biological preparations, mass trapping and mating disruption with the help of pheromones. Chemical: repeated treatments with insecticides from the start of flowering. Quarantine actions: examination of imported fruits; regulated delivery of planting and grafting material of susceptible cultures from regions of pest distribution.Related references.
Danilevskii A.S., Kuznetsov V.I. 1968. Tortricidae, tribe Laspeyresiini. Moscow & Leningrad: AN SSSR, 636 p. (Bykhovskii B.E., ed. Fauna of the USSR, new ser., N 98. Lepidoptera. V. 5(1)). (in Russian).Kostyuk Yu.A. 1974. Family Tortricidae. In: Vasil.ev, V.P., ed. Pests of agricultural crops and forest plantations. V.2. Arthropods. Kiev: Urozhai, p. 261-320 (in Russian).
Kuznetsov V.I. 1994. Family Tortricidae. In: Kuznetsov, V.I., ed. Insects and mites - pests of agricultural plants. V. 3(1).Lepidoptera. St.Petersburg: Nauka, p. 51-234 (in Russian).
Shutova N.N., Smetnik A.I. 1986. Quarantine pests, diseases and weeds. In: Shamonin A.I., Smetnik A.I., eds. Plant quarantine in the USSR. Moscow: Agropomizdat, p. 143-248 (in Russian).
Vasil.ev V.P., Livshits I.Z. 1984. Pests of fruit crops. Moscow: Kolos, 399 p. (in Russian).